台灣入侵紅火蟻與熱帶火蟻毒液生物鹼的化學生態與殺蟲毒理之研究

Chemical ecology and toxicology of venom alkaloids in red imported fire ant (Solenopsis invicta) and tropical fire ant (S. geminata) in Taiwan

賴麗娟(Li-Chuan Lai)

指導教授 ： 吳文哲

共同指導教授 ： 黃榮南(Rong-Nan Huang)

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/博士(2009年)

https://doi.org/10.6342/NTU.2009.00527

摘要

台灣為入侵紅火蟻 (Solenopsis invicta) 的新發生地，熱帶火蟻 (S. geminata) 則已入侵台灣南部多年，此兩種外來火蟻的攻擊力強，毒液含90% 到95%生物鹼及少量毒蛋白，生物鹼具有抗菌、溶血、殺蟲以及刺激組織釋放組織胺的功能；毒液內四種毒蛋白主要引起過敏反應。由於入侵紅火蟻在台灣已被發現具單蟻后與多蟻后兩社會型，因此本研究針對入侵紅火蟻兩社會型及熱帶火蟻之毒液生物鹼 (venom alkaloids) 進行探討與比較。除了調查台灣之生態環境及氣候對毒液生物鹼組成的影響外，同時於實驗室以不同生長溫度飼養火蟻，採不同方法收集毒液，再利用氣相層析質譜分析儀 (gas chromatography coupled to mass spectrometry, GC-MS) 分析毒液生物鹼的變化。研究結果顯示，單蟻后型與多蟻后型入侵紅火蟻的毒液中均含六種主要的反式結構生物鹼，熱帶火蟻的毒液則具兩種主要生物鹼。抽取毒液方法、生長溫度、季節、採集地點等均不會影響入侵紅火蟻兩社會型的生物鹼組成，且單蟻后型入侵紅火蟻毒液中不飽和生物鹼總和均顯著低於多蟻后型；此外，由於C13 (C13:C13:1) 與C15 (C15:C15:1) 生物鹼在毒液中含量最高，因此進行兩社會型C13與C15比值的比較，發現單蟻后型C13與C15比值均顯著高於多蟻后型。自中台灣 (台中與彰化) 與南台灣 (台南) 所採集到的熱帶火蟻，鑑定後皆屬單蟻后社會型；本研究比較熱帶火蟻兵蟻與工蟻兩階級的毒液生物鹼中cis C11與trans C11的比值，兵蟻的cis C11與trans C11比值顯著高於工蟻；工蟻的cis C11與trans C11比值並不會受到飼養於四種不同溫度的影響；但春季所採集到的工蟻其毒液內的cis C11: trans C11比值最高，而冬季所採得的工蟻毒液內其比值最低。在熱帶火蟻體型與毒液量關係的探討中，發現兵蟻的頭長、頭寬、腹長、體長與毒液量均與工蟻有顯著差異；此外無論是兵蟻或工蟻，其頭長、頭寬、腹長、體長與毒液量皆呈正相關性。利用火蟻毒液的特性，進一步以純毒液塗抹於3至4齡小菜蛾的表皮，或直接以火蟻螫刺小菜蛾與3齡斜紋夜蛾幼蟲；小菜蛾幼蟲的表皮經毒液作用後會逐漸變黑，麻痺，最後全身變黑死亡。從組織切片可看出，以單蟻后型和多蟻后型入侵紅火蟻，以及熱帶火蟻毒液處理的小菜蛾組織比未處理的控制組明顯受到破壞，甚至有細胞溶解、黑色素累積等現象。斜紋夜蛾幼蟲經火蟻螫刺後會顫抖、偶而抽慉，逐漸麻痺，最後全身水腫、死亡。從斜紋夜蛾幼蟲的死亡率，以及對火蟻毒液之敏感性，可知熱帶火蟻毒液之毒性最強，其次是入侵紅火蟻單蟻后型，最弱的是入侵紅火蟻多蟻后型。由於火蟻的毒液彷如雞尾酒般，靠著互相作用來殺敵或麻痺獵物，因此利用火蟻毒液處理農業害蟲的方式，觀察並比較不同種火蟻毒液對小菜蛾與斜紋夜蛾幼蟲的作用，以期瞭解火蟻毒液之毒殺特性其對農業生態之影響。

關鍵字

入侵紅火蟻 ； 熱帶火蟻 ； 毒液生物鹼 ； 不飽和生物鹼 ； 小菜蛾 ； 斜紋夜蛾 ； 黑色素

並列摘要

The red imported fire ant (RIFA), Solenopsis invicta was first discovered in Taiwan in 2003, and both monogyny and polygyny were characterized simultaneously. The tropical fire ant (TFA), Solenopsis geminata was introduced into southern Taiwan many years ago and has continued to threaten the residents. Fire ant venom contains about 90% to 95% water insoluble alkaloids and a small amount of protein. The alkaloids exhibit antibacterial, hemolytic, insecticidal and histamine-releasing properties, whereas the four major protein allergens in the worker venom are responsible for anaphylactic reactions. Because of both monogyne and polygyne colonies of S. invicta now occupy Taiwan, the venom alkaloids from workers of both social forms in S. invicta and from workers in S. geminata were investigated. The venom alkaloids were studied by gas chromatography coupled to mass spectrometry (GC-MS). Six major venom alkaloids were detectable in both social forms of workers of S. invicta and two major venom alkaloids were detectable in workers and soldiers of S. geminata. The sum of proportions of unsaturated alkaloids from polygyne workers was significantly higher than that from monogyne workers of S. invicta, regardless of rearing temperatures, sampling seasons or geographic locations. Both C13:C13:1 and C15:C15:1 ratios in alkaloid venom of monogyne workers were statistically higher than that of polygyne workers. All examined nests of S. geminata collected from central Taiwan (Taichung City and Changhua County) and southern Taiwan (Tainan City) represent monogyne form only. The results also revealed that the ratio of cis C11 to trans C11 alkaloids in soldiers was significantly higher than that in workers of S. geminata. There was no statistically significant difference on the relative alkaloids content and the ratio of cis C11 to trans C11 alkaloids in venom while workers were reared at four temperature conditions. Nevertheless, the ratio of cis C11 to trans C11 alkaloids in the venom of workers was the highest in spring and lowest in winter. Our results showed that the head length, head width, abdomen length, body length and venom volume differed significantly between soldiers and workers of S. geminata. Furthermore, the head length, head width, abdomen length and body length were positively correlated with venom volume in soldiers and workers of S. geminata. The third to fourth instar larvae of Plutella xylostella and the third instar larvae of Spodoptera litura were treated with fire ant’s venom. The diamondback moth larva which treated with venom became black, paralysis and died after 24 hours. The sections of larvae of diamondback moth indicated that cells lyse and the accumulation of melanins. Fire ant venom-induced symptoms in Sp. litura larvae include contractile, flaccid paralysis and edema. The order of toxicity of fire ants venom was TFA > RIFA (M) > RIFA (P). The venoms from these fire ants are complex cocktail, which evolved for the purpose of killing or paralyzing prey. The objective of toxicity of fire ant venom toward the P. xylostella and Sp. litura larvae was to understand the effects of venom on agricultural ecology.

並列關鍵字

Solenopsis invicta ； Solenopsis geminata ； venom alkaloids ； unsaturated alkaloids ； Plutella xylostella ； Spodoptera litura ； melanin

參考文獻

Allen, C. R., D. M. Epperson, and A. S. Garmestani. 2004. Red imported fire ant impacts on wildlife: A decade of research. Am. Midl. Nat. 152: 88-103.

Arbiser, J. L., T. Kau, M. Konar, K. Narra, R. Ramchandran, S. A. Summers, C. J. Vlahos, K. Ye, B. N. Perry, W. Matter, A. Fischl, J. Cook, P. A. Silver, J. Bain, P. Cohen, D. Whitmire, S. Furness, B. Govindarajan, and J. P. Bowen. 2007. Solenopsin, the alkaloidal component of the fire ant (Solenopsis invicta), is a naturally occurring inhibitor of phosphatidylinositol-3-kinase signaling and angiogenesis. Blood 109: 560-565.

Baer, H., T. Y. Liu, M. C. Anderson, M. Blum, W. H. Schmid, and F. J. James. 1979. Protein components of fire ant venom (Solenopsis invicta). Toxicon 17: 397-405.

Banks, W. A., J. K. Plumley, and D. M. Hicks. 1973. Polygyny in the tropical fire ant, Solenopsis geminata. Ann. Entomol. Soc. Am. 66: 234-235.

Blum, M. S., J. R. Walker, P. S. Callahan, and A. F. Novak. 1958. Chemical, insecticidal, and antibiotic properties of fire ant venom. Science 128: 306-307.